The present invention relates to a method for operating a corner burner for a tangential burner system in which via the corner burner at least one stream of coal dust and primary air and optionally a further stream of combustion air and/or returned flue gas is tangentially introduced onto an imaginary and substantially horizontal circle within the combustion chamber of the tangentially burner system. At least one further air stream (wall air stream) is introduced by a nozzle of the corner burner at an adjustable off set angle relative to the stream of coal dust and primary air into the combustion chamber in a direction toward a wall of the combustion chamber.
From European patent document EP 22 454 B1 such a method is known in which a secondary air stream is introduced into the combustion chamber such that the secondary air stream is oriented tangentially onto a second imaginary circle which is spaced at a distance coaxially and radially outwardly to the first imaginary circle. The secondary air stream is designed to produce an oxidizing atmosphere along the combustion chamber walls in order to reduce thus the formation of slack and corrosion at the respective combustion chamber wall. Preferably, the nozzle for the stream of coal dust and primary air and the nozzle for the secondary air stream are vertically arranged above one another, as is, for example shown in FIG. 5 of EP 22 454 B1. The orientation of the secondary air stream onto a second imaginary circle corresponds to an offset angle of the secondary air stream relative to the flow of coal dust and primary air in the direction onto the wall of the combustion chamber. According to column 5, lines 50-59, of this printed document, the nozzle is provided with a pivoting device for the additional air stream (secondary air stream or wall air stream).
Such mechanical pivoting devices are complicated in their manufacture and are disadvantageously exposed to the high combustion chamber temperatures.
It is therefore an object of the present invention to provide a method for operating a corner burner of a tangential burner system with which the adjustability of the secondary air stream (wall air stream) is possible without mechanical pivoting devices.